This project develops methods to assess patient preferences toward alternative states of health for use in cost-effectiveness analysis of pharmaceutical therapies. Its uses multimedia-based computer interviews in order to measure aspects of health, to refine risk-risk and risk- dollar tradeoff techniques for preference assessment, and its implements several tests of reliability and of validity. The preference assessment technology is then applied to cost-effectiveness analysis of alglucerase, a new treatment of Gaucher disease. For this drug, like many others effects on quality of life are likely to be more important than survival effects. The results of the analysis should help to quantify interindividual variation in preferences, and intertemporal consistency in preferences. If successful, the project will produce an easily-implemented and reliable instrument for the assessment of preferences and quality of life for use in cost-effectiveness analyses.